We recently had a meetup event where Kyle Weiss talked about Persona definition for consumer apps. He walked through the process of initially defining a persona and then how to refine and re-evaluate once you have had a chance to validate assumptions with data. The slides and personas he presented are attached.

One thing to note, this process was geared towards new concepts and new ideas and should be modified for existing B2B orgs or where a business already exists. Understand who your paying customer is, will always be more important than trying to define who they “should” or “could” be.